Heading to Laos we decided to take the famous slow boat across the Mekong River, from Huay Xai in North Thailand to Luand Prabang in Laos. The boat sails for 2 days with an overnight stop in the Lao village of Pakbeng. Your other option is taking a bus which supposedly takes about 14 hours and is very uncomfortable, or of course the quickest and most expensive way of catching a flight from Chiang Mai to Luang Prabang (direct flight with Lao airlines is about 110$). Despite the long journey the boat ride turned out to be a great experience and we recommend it if you are not pressed for time.